Launching and hauling out small boats is becoming more and more difficult where special facilities are not provided. Larger and larger outboard engines add to the problem. These have gone well beyond the point where a man can unclamp the engine from the transom, lift it off, and carry it over to the trunk of his car. Small boats that used to be appropriate for local fishing now do double duty for water-skiing, and with a consequent increase in required horsepower. Deep trolling in large bodies of water has also shifted emphasis to much more substantial and seaworthy hulls.
Moving these more massive boats into and out of the water becomes further complicated if the shoreline is strewn with sizeable rocks, rather than providing a smooth sand beach. Running the boat up on the shore becomes out of the question. Marine railways have come into common use by owners of shoreline property. Even these installations present problems in rough weather. Wave action can bounce the boat to the point that it drops down hard enough on the railway carriage to damage the hull. In the usual case, a boat operator must somehow get to and from his boat while it is afloat, and the bouncing of wave action can easily shift the boat out of the aligning effect of the carriage. The operator usually has to walk around in knee-deep water in the midst of the rocks, as a conventional marine railway is moved by winch and cable controlled from on-shore.